Definition: In this task, you are given an input list A. You need to convert all the alphabets in the list with a number representing their position in the English alphabet. E.g., replace A by 1, B by 2, a by 1, b by 2, and so on.
Input: ['D', '9937', 'A', '5383', '4829', '8839', 'L']

4, 9937, 1, 5383, 4829, 8839, 12